1. Field of the Invention
The present invention relates to an analyzer for automatically analyzing blood coagulation in a clinical laboratory.
2. Description of the Background Art
In order to measure blood coagulation, a sample and a reagent are introduced into a cell, which in turn is moved to a coagulation measuring portion. In a general blood coagulation analyzer, such a measuring portion is provided with a photometer for irradiating the cell with a measuring beam emitted from a light source and detecting light scattered by a sample reaction solution with a photodetector.
In one of such conventional analyzers, a plurality of measuring portions are so provided that cells numbering the same as the measuring portions are successively transferred thereto for carrying out parallel processing, in order to improve processability for the blood coagulation analysis.
In another conventional blood coagulation analyzer, a cell containing a sample and at least one reagent can be selectively transferred to one of a plurality of measuring portions (refer to Japanese Patent Laying-Open Gazette No. 61-280572 (1986)).
However, coagulation times are varied with samples. In a conventional analyzer which successively transfers cells to fixed coagulation measuring portions, therefore, it is necessary to set a cycle time in response to a measurement item having the longest reaction time. Thus, it is difficult to improve processability of such an analyzer.
On the other hand, an analyzer which can selectively transfer a cell to any one of a plurality of measuring portions requires a complicated mechanism having a number of moving systems for moving every cell to a prescribed position in order to dispense a sample, dispense a reagent and mount/dismount the cell.
Further, reagent dispensation may be required once or twice, depending on the measurement items. For example, reagent dispensation may be carried out only once in PT (prothrombin time), FIB (fibrinogen), T(thrombo test) H (hepaplastin test), while actin must be previously dispensed as a reagent in APTT (activated part thromboplastin time) for activating a reaction solution of the reagent and the sample for a constant time, so that another reagent for serving as a trigger is thereafter dispensed. When sample dispensation or reagent dispensation is controlled in a random access manner, therefore, it may be necessary to dispense reagents in two cells during one cycle. Therefore, the aforementioned analyzer which can selectively transfer the cell to one of a plurality of measuring portions requires a complicated high-speed operation for successively transferring two cells to a single reagent dispensing position in a single cycle. Thus, the cycle time must be increased, to disadvantageously hinder improvement of processability.